The problem was so much land and so few white settlers and this was before mechanization. Please correct me if I am wrong but a wheat farmer in ND can farm a couple thousand acres with very little help with the right equipment.
You are correct. The equipment costs are large, so the scale of the farm is, too. Not uncommon for a farmer in these parts to have between 5 and 10 sections (each section is a square mile, more or less, about 640 acres) in crops. Some farm more. The equipment to farm that, though, is upwards of a million dollars new.